The present invention relates generally to a locating table apparatus. More particularly, the present invention relates to the locating table apparatus preferably employed for a robot operable in a cartesian coordinate system and a precise locating apparatus for production of semiconductors or the like.
In general, a conventional locating table apparatus is constructed such that a table is supported to freely move in one direction with the linear movement guiding members arranged on a base stand so that the table is moved in the direction along a screw shaft by rotating the screw shaft. In addition, another conventional locating table apparatus is also known of the type providing a housing of which side and upper surfaces are covered with dustproof covers.
For example, as shown in FIG. 7 which is a cross-sectional view showing a conventional locating table apparatus designated by reference numeral 200. The locating table apparatus 200 provides a ball screw unit 20. A screw shaft 20a of the ball screw unit 20 is rotatably supported with support members fixedly mounted on a base stand 31 at both ends of the screw shaft 20a. The screw shaft 20a is operatively linked to a motor (not shown) so as to be rotationally driven. A ball screw nut 20b threadably fitted onto the screw shaft 20a is fixedly provided on a bracket 24 secured onto a lower surface of a table 25. Bearings 27b of a linear guide unit 27 are fixedly disposed on both ends of the lower surface of the table 25 via spacer 26, and each of the bearings 27b is constructed so as to move in a axial direction along linear movement guiding rails 27a.
The table 25 of the locating table apparatus 200 is sealed with a dustproof cover 30 forming two slits 29 extending in the axial direction on an upper surface thereof. Projections 25a formed on both the sides of the table 25 are upwardly projected, and a moved member (e.g., an operating table) is mounted on the projections 25a through the slits 29 of the dustproof cover 30.
With the location table apparatus 200 constructed in the above-described manner, when the motor is driven to rotate the screw shaft 20a, the ball screw nut 20b is moved along the screw shaft 20a corresponding to rotational directions thereof, so that the table 25 is moved in the axial direction. Although the table of the conventional locating table apparatus is sealed with the dustproof cover, a soundproof function is not taken into account. Therefore, there is a problem that noisy sound is generated inside the locating table apparatus during an operation thereof.